Objective: To study the enzymes and control mechanisms of heme and chlorophyll biosynthesis in cells producing hemoglobin; in liver cells producing heme proteins including P450; and in developing chloroplasts producing chlorophyll. A. Enzymes in red blood cells will be used to provide a basis for micro-assays of lead poisoning, iron deficiency anemia, for Acute Intermittent Porphyria (AIP) and other porphyria diseases. The Genetic inheritance of two of these enzymes, including the one for AIP will be studied. Friend Leukemia cells will be used to determine the control by 5 beta-H steroids on delta-aminolevulinic acid synthetase (ALA-S), the rate controlling enzyme of heme biosynthesis. B. Chick embryo liver cells in culture will provide a simple system to study the control on ALA-S at the transcriptional, nd translationsl levels and also to study the transport o ALA-S into the mitochondrion where it is functional. The follow controls in a cell free system, antibodies will be prepared to ALA-S. It is also proposed to study serum albumin synthesis in chick embryo liver to seek for a hormonal control responsive to osmotic pressure. C. In barley seedlings a brief exposure to weak light causes a marked increase in ALA-S activity and a resulting increase in chlorophyll synthesis. This important control mechanism governed by light is being exmined using metabolic inhibitors and barley mutants.